A directory is missing from your repository

Rails expects certain directories to be present in your app, including log/, tmp/ and occasionally others. If they are not in your repository, your tests will fail (though they ran fine locally because you created the directory a long time ago).

To fix this, simply add the directory to your repository. Git doesn’t allow you to add directories to it, but the standard idiom is instead to add a file called .gitkeep within the directory. So this should solve your problem:

$ touch log/.gitkeep
$ git add log/.gitkeep
$ git commit

If this solution is unacceptable (perhaps you symlink your log directory in production), you can also add a post-checkout command to create the directory:

checkout:
  post:
    - mkdir -p log